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Two different time-resolved spectroscopic techniques are discussed theoretically and demonstrated experimentally in dilute gases. The first technique involves extending the advantages of Stark-effect based time-resolved spectroscopy to non-polar molecules. This involves the development of a stable, TEM₀₀ mode, cw, CO₂ laser capable of switching rapidly and controllably between two frequencies. Design problems and output characteristics are discussed. The frequency switchable laser is applied to the CO₂ 10.6 μm P(16) coincidence with the non-polar molecule SF₆. The population relaxation time, T₁, is measured using two-pulse delayed nutation. The decay of induced dipoles is studied using the phenomenon of photon echoes. It is found that the echoes decay in a manner characteristic of dephasing dominated by velocity-changing collisions. A fit of the data to a model for such decays gives values of γ(ab) ≡ 1/T₂ (the non-velocity-changing contribution to the dipole decay rate), Γ(VC) (the total probability of a velocity-changing collision per unit time), and Δu which is related to the mean velocity change of SF₆ upon a velocity changing collision. A comparison with the published results of the similar Stark experiments on C¹³ H₃F are made. The second technique involves the development of an alternative to the pulsed excitation typically used in time-resolved T₁ studies. This involves inversion of a portion of the velocity distribution by adiabatic rapid passage (ARP) techniques. The center of this portion is then probed in the manner of previous delayed nutation experiments. The system preparation is shown theoretically to be different and simpler than the pulse case. In addition, ARP preparation gives a larger signal than two-pulse delayed nutation experiments. ARP experiments on N¹⁴H₃ and N¹⁵H₃ are described and compared to two-pulse delayed notation experiments. The single exponential decay best fits to the data from the two methods are found to be in agreement. We would expect the N¹⁵H₃ results to be very similar to the N¹⁴H₃ results, though reduced rotational resonance effects in its upper state should give it an overall slower decay. It is indeed found that the decay appears to be a simple exponential as did the N¹⁴H₃ data over the time range studied. The pressure dependent single exponential decay rate for N¹⁵H₃ is however roughly 45% larger than the rate for N¹⁴H₃ in the pressure range from 0.5 to 9 mTorr.

This dissertation describes the study of various nonlinear optical effects in both bulk and quantum-confined semiconductors. Transverse effects in increasing absorption optical bistability are considered in bulk CdS for both single beam and wave mixing geometries. Measurement of the temporal response of BiI₃ quantum dots is described using degenerate four-wave mixing and explained theoretically. Finally, the experimental techniques developed to measure the one- and two-photon absorption coefficients of CdS quantum dots in glass are described along with the latest theoretical description and interpretation of the experimental spectra. The basic theory of increasing absorption optical bistability is presented along with experimental observation of this effect in CdS at low temperature. Transverse effects in increasing absorption optical bistability were observed in single beam experiments with CdS at low temperatures. The ring structures observed experimentally are explained theoretically. Degenerate four-wave mixing performed with this nonlinearity is theoretically shown to produce new scattering orders compared with a standard Kerr analysis. Experimental observation of these new scattering orders is presented. The temporal response of the nonlinearity in a solution of BiI₃ quantum dots in acetonitrile is determined using degenerate four-wave mixing. The independent contributions to the phase-conjugate signal are determined for both of the spatial gratings induced in the solution. The observed temporal responses indicated that a thermal mechanism was responsible for the nonlinearity. A theoretical analysis based on a thermal nonlinearity is presented which provides good agreement with the observed responses. The experimental techniques necessary to measure the one- and two-photon absorption coefficients of CdS quantum dots are described. The resultant measurements of quantum dot samples with microcrystallites ranging from 3.6 to 10.8 nm in diameter indicate no splitting of the energy levels associated with the hole. Theoretical spectra indicate this can be partially explained by the inclusion of Coulombic effects of the charged electron-hole pair.

The Combined Laser and Scan Sonar (CLASS) system is an extended range imaging system, incorporating both high-resolution laser images and high frequency sonar images. Both the laser and sonar images are collected simultaneously during testing to provide dual mode imagery of an underwater target, displaying both a 2D image of the target (laser image) and a 3D overlay of the target (sonar image). The laser component of the system is a Multiple Overlapping Field of view Serial Laser Imager (MOFSLI), capable of generating high-resolution sub-centimeter 2D images. MOFSLI generates the images by way of a near diffraction-limited 532 [nm] continuous wave (CW) laser beam being scanned over the target. Initial field tests resulted in high-quality images of the ocean floor, but also indicated the need for additional research on MOFSLI. In this thesis, we focus on the calibration of MOFSLI and on the evaluation of the image quality generated by this system, as a function of range, source power, receiver gain and water turbidity. This work was completed in the specialized underwater electrooptics testing facility located in the Ocean Visibility and Optics laboratory at Harbor Branch Oceanographic Institute (HBOI). Laboratory testing revealed the operational limits of the system, which functioned well until just beyond five attenuation lengths, where it becomes contrast limited due attenuation of target signal and the collection of non-image bearing backscattered photons. Testing also revealed the optimal settings of the system at given environmental conditions. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

Yuen Chi Yan = 有關光折變晶體中空間孤子、偏振轉動以及霍爾效應的研究 / 阮志仁. / Thesis submitted in: July 2004. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 81-82). / Text in English; abstracts in English and Chinese. / Yuen Chi Yan = You guan guang zhe bian jing ti zhong kong jian gu zi, pian zhen zhuan dong yi ji Huoer xiao ying de yan jiu / Ruan Zhiren. / Acknowledgments --- p.i / Abstract --- p.ii / Table of Contents --- p.v / Chapter Chapter 1 --- Photorefractive Spatial Soliton --- p.1 / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Bright Spatial Soliton --- p.3 / Chapter 1.2.1 --- Experiment --- p.4 / Chapter 1.2.2 --- Results and Discussion --- p.6 / Chapter 1.2.2.1 --- Expansion --- p.6 / Chapter 1.2.2.2 --- Contraction --- p.10 / Chapter 1.3 --- Dark Spatial Soliton --- p.15 / Chapter 1.3.1 --- Experiment --- p.15 / Chapter 1.3.2 --- Results and Discussion --- p.20 / Chapter Chapter 2 --- Polarization Rotation --- p.23 / Chapter 2.1 --- Introduction --- p.23 / Chapter 2.2 --- Experiment --- p.24 / Chapter 2.3 --- Results and Discussion --- p.30 / Chapter 2.3.1 --- Effect of varying pump beam power --- p.30 / Chapter 2.3.2 --- Effect of different polarizations of signal beam --- p.41 / Chapter 2.3.3 --- Effect of signal beam size --- p.43 / Chapter 2.3.4 --- Effect of applied E-field --- p.46 / Chapter 2.3.5 --- Effect of signal beam and pump beam separation and perpendicularly --- p.52 / Chapter 2.3.6 --- Investigation of Δne using interferometer --- p.60 / Chapter 2.3.7 --- Computer Simulation --- p.69 / Chapter Chapter 3 --- Hall Effect --- p.72 / Chapter 3.1 --- Introduction --- p.72 / Chapter 3.2 --- Experiment --- p.75 / Chapter 3.3 --- Results and Discussion --- p.76 / Conclusion and Possible Further Works --- p.79 / References --- p.81

A metal-oxide-silicon (MOS) tunneling diode is utilized to embed beta-FeSi 2 precipitates and give strong 1.5 tam electroluminescence at 80 K. And this simple MOS structure with beta-FeSi2 was fabricated by Fe ion implantation and rapid thermal oxidation (RTO) at 900°C, which is fully compatible with ultra-large scale integration (ULSI) processes. / beta-FeSi2 precipitates are also incorporated into a silicon-on-insulator (SOI) rib waveguide and a p+-i-n+ photodetector is monolithically integrated with this SOI rib waveguide. The photoresponse to 1550 nm laser of beta-FeSi2 precipitates was observed and compared to intrinsic silicon. / Beta-phase iron disilicide (beta-FeSi2) is a semiconductor that can act as a light emitting material at the wavelength of 1.55 mum and can also be grown epitaxially on Si substrates. In this thesis, Fe ion implantation into silicon using a metal vapor vacuum arc (MEVVA) ion source was performed to synthesize nano-scale beta-FeSi2 precipitates in silicon matrix. The implantation was performed at ∼-120°C and the effects of silicon substrate and conditions for the following thermal annealing on luminescence properties were studied. The samples were characterized by employing various analytical techniques including Rutherford backscattering spectrometry (RBS), transmission electron microscopy (TEM), atomic force microscope (AFM), photoluminescence (PL), and electroluminescence (EL). / It is found that the PL intensity is optimized in p-100 silicon substrates (with the resistivity of 15-25 O·cm) using Fe ion implantation at a voltage of 80 kV and dosage of 5x1015 cm -2. Formation of beta-FeSi2 can be completed after rapid thermal annealing (RTA) and strong photoluminescence is present. We also found that RTA could maintain the strain in beta-FeSi2 precipitates and there exists an epitaxial relationship between beta-FeSi2 and silicon. Additional furnace annealing at 850°C can relax the strain in beta-FeSi2 precipitates. / The development of both modern microelectronics and lightwave technologies has enabled the establishment of the Internet which has introduced a profound change in our everyday lives. Because of Moore's law, computing today is limited less by the computation ability of microprocessors than by the rate at which the processor can communicate with the outside world. Lightwave technology has had many successes in the long-haul communication field over the past decade. The advantages of lightwave technology over conventional electronics are becoming apparent for shorter and shorter reach applications and lightwave communications may eventually replace copper-based interconnects in microelectronics. To make possible optical interconnects, optical components, especially light emitters may be needed to be integrated on conventional silicon microchips. However, to date, no efficient on-chip silicon-based light emitter is fabricated in silicon photonics. / Sun, Caiming. / Adviser: Hon K. Tsang. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3703. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.

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